The present invention relates to an improved sealing arrangement in an air-cooled electronic module, and more particularly to a sealing arrangement for a modular avionics package which is cooled by flowing air through a module frame.
There is a constant demand for smaller electrical and electronic components, particularly in the aircraft and missile fields, as weight is of extreme importance. One concept of microelectronics which has been recently developed and which offers a great reduction in size and weight of electronic units is that of integrated circuitry which is formed on insulated bases such as glass, fused silica, or ceramic substrates. Integrated circuitry includes a number of active and passive components which are fabricated by one or more of a combination of several thin film deposition techniques onto a glass or ceramic substrate.
In order to reduce costs, expedite production, and provide a reliable electronic component, a standard hardware program has been formulated in which electronic plug-in modules have been developed which are capable of meeting various system requirements. One such plug-in module is shown in U.S. Pat. No. 3,243,660, entitled "Electronic Module Assembly", which issued Mar. 29, 1966, to Leonard J. Yuska and David P. Zimmerman.
One concept of a standard hardware program is to have a plurality of modules which plug in a chassis to form an assembly and normally these plug-in modules slide in grooves or ways in the chassis and engage a mating female connector. These modules are closely assembled and dissipate considerable thermal energy which, if not removed, greatly affects component reliability.
Various attempts have been made to cool electronic assemblies and generally employ some type of cooling coil and fan assembly. One such device is shown in U.S. Pat. No. 2,187,011, entitled, "Cooling Means For An Electrical Apparatus", which issued Jan. 16, 1940, to Paul F. Braden. In one embodiment of this patent, a fan blows air over a cooling coil and the air passes successively through three shelves which support vacuum tubes and other electrical components. The disadvantage of such an arrangement, however, is that the first shelf receives cool air, which is heated by the electrical components, and the last shelf receives hot air and experiences little or no cooling effect.
In U.S. Pat. No. 3,942,586, entitled, "Cooling Arrangement For Flat Semiconductor Components", which issued Mar. 9, 1976, to Paul Fries, the inventor recognized a need for cooling all the mounted components. He stated that there is a need for an improved cooling arrangement for stacked flat semiconductors which can: (1) take advantage of the benefits of the heat pipe; and (2) in addition, provide adequate cooling to the semiconductors no matter what their location is within the column or stack. That is, the problem is to provide an arrangement in which cooling air of essentially the same temperature can flow over all the heat pipes in such an arrangement. The solution proposed was to axially align the semiconductor components, with the axes of the heat pipes of the cooling elements which are located one over the other, arranged so that they are rotationally displaced with respect to each other about the stack axis.
In U.S. Pat. No. 4,315,300, which issued Feb. 9, 1982, to James K. Parmerlee and B. Dale Tague, an improved cooling arrangement is shown for an electronic plug-in module assembly having a plurality of modules supported in grooves in a pair of parallel sides. Each parallel side is provided with fluid passageways for carrying a cooling liquid for removing heat transferred from a heat sink on each module to the sides. A plurality of apertures are provide in each side between adjacent grooves and carry fins through which cool air is blown to cool each side of each plug-in module. One disadvantage of such and arrangement, however, is that the cooling air flowing over the electronic components presents a corrosion problem.